Well there is an amazing library of great games for the PS4 so far.
If RPG's are your favorite I have a few games here for you good sir:
The Witcher 3 - A wonderful adventure where you will travel across a huge world map fighting all sorts of dangerous creatures. The sidestories are interesting and the writing is mostly top notch. Takes a little while to get going but the game looks stunning.
Persona 5 - I personally was new to the whole Persona series before I bought and finished this game in about 110 hours. It's one of the best JRPG'S in recent years if you ask me, and stands up there with the greats. You basically have your dungeon crawling, Pokèmon style collecting of various demons, angels and mythical creatires who will fight for you in battle. Besides that there is a huge story and basically social RPG element on top of that, which gives you the ability to "level up" various stats like Knowledge and Kindness, which in turn help you become closer with various NPC's you meet. A really deep JRPG with an amazing combat system and a very groovy soundtrack. A great first step into the Persona series!
Bloodborne - For me personally this is one of the best "Souls" games. FromSoft and Miyazaki really outdid themselves with this game. The mood is perfectly Lovecraftian mixed with a very tense and opressive feeling of dread surrounding you at all times. Amazing bossfights and another great combat system. This new entry to the Souls series introduces various Trick weapons that can transform at your will, and are very versatile due to that fact.
Nioh - Nioh is another "Souls" type game, but heavily influenced by games like Ninja Gaiden and Diablo 3. It plays much much faster then your typical "Souls" game, even more so than Bloodborne. This game features a heavy focus on Ninja, Magic and Japanese history. More Level based than say Dark Souls where it's one open world, but that feels very fresh. The combat system is deeper than most RPG's because you can fully customize your skills and each weapon type has various stances (low,mid,high) which impacts the moves at your disposal. Another amazing title.
Some other titles that should not be forgotten:
The last of Us Remastered
Uncharted 4
Until Dawn
Driveclub